Mineral oil compositions



Patented Mar. 11, 1952 UNITED STATES PATENT "OFFICE MINERAL OILCOMPOSITIONS- Albert G. Rocchini, Springdale,1Pa.,. assignori to GulfResearch & Development .Company, Pittsburgh, Pa., a corporation ofDelaware No Drawing. Applicationsepteniber16;19 i8,

' Serial No. 49,660

5 Claims. (Cl.-25251.5)

This invention relates to mineral oil-compositions, and in particularconcerns mineral oil compositions adapted to protect ferrous and othermetalsurfaces with which they come in contact "from rustin 'and othertypes of corrosion.

As is well known, simple mineral oil films afiord only limitedprotection to metal surfaces against rusting and other types ofcorrosion, and in eneral cannot be relied upon to provide sufiicientprotectioninthe presence of'moisture or even under conditions of highhumidity. "quent'ly, it has become common practice to employConsecorrosioninhibitors or anticorrosion agents as additives in mineraloil compositions for the purpose of: providing additonal protectionagainst rusting and corrosion. Such additives have been used in varioustypes of lubricating compositions,

such as machine oils, turbine oils, internal combustion engine anddiesel lubricating oils. greases,

Others of the compositions in which they are used, c. g., lubricatingvalue, demulsibility, etc.

Accordingly, it is an object of the present invention to provide mineraloil compositions which protect metal surfaces with which they come incontact against rusting and corrosion underextreme conditions ofservice.

Another object is to provide mineral oil compositions capable ofprotecting metal surfaces 1 against corrosion even by salt water.

A further object is to provide improved mineral 1 oil i compositionscontaining an effective anticorrosion additive which does not adverselyaiiect thedesirable prope ties of the oil itself.

herein-will occur to those skilled in the art upon- "em loyment of theinvention in practice.

I have now found that t e above ob ects and "-attendantadvantages may berealized by incorporating into mineral oil compositions as ananticorrosionwadditive ta minor amount of a waterinsoluble, oil-soluble"reaction ::product between an aliphatic dicarboxyliczacidanhydrideconstaining as a substituentira hydrocarbon :radical .suchas analkyl, aryl, alkenyl, aralkyl, oncycloalkyl radical'and a tertiary:amine. I;,-have1tound that reaction products'of this class are particu-1 larly well adapted-for uses asanticorrosiomadditives for mineraloils,since they efiectively inhibit rusting and corrosion of metals,and'atlthezsame time do not adverselyafiect the lubricatingproperties ofthe oil.

The reaction products between ethersubstituted aliphatic dicarboxylicacid :anhydrides: and :the

tertiary amines can be prepared ina simplermanner. I havefound-thattthey can be prepared efficiently by mixing equiv-molecularquantities of the anhydrideand the amine. In most cases the reactionbeginsuponuadmixture, but if eVidence of reaction is not, immediatelyapparent, heatin is desirable inorder=to=start=the-reaction. To insureadequacyof reaction themixture should attain an elevated temperature;preferably atemperature of at least 250F. Where the heat of reaction. issuilicient to raise' the temperature of the mixtureat least to thispoint, no additional heat is required, but where:necessary it isadvisable toheatthe'mixturezto' the temperature in question which shouldbe maintained for atieast'five minutes. -The'products obtained areinsoluble in water i and are -soluble in oil at "least to: an extentsufiicient to: permit their solution inoil'l-in anfwamount equal-toatleast 0.005 per cent and preferablywat-least 1.0 per cent.The"preferred'=-reaction productsare obtained fromsubstituted:aliphatic: dicarboxylic acid anhydrides inrwhich the-substituent;con-

tainsat least six carbonatoms.

The reaction products aprepared as described above and adapted for usein the r compositions of the invention are relativelyhigh boiling,lightcolored, viscous liquids {to .darker-coloredpsemiliquids 1 or softresinous solids. 'Inaddition "to being sufliciently soluble in mineraloils to act'as very effective corrosioninhibitorspthey are also solublein such organic solvents -as hexane. chloroform; and benzene.

'The specific chemical nature "of the reaction products employed inaccordance-with the invention is not understood. Since they "areprepared under anhydrousconditions employing the acid anhydride, theyarenot simple'salts of the corresponding acid and the amine. Moreover,

salts between the acids and the' amines are" sold-- ble in water,=whereas'the' reaction=-productswith which this invention is concernedare substanwith water.

tially water-insoluble. On the other hand, all evidence indicates thatthe reaction products are not amides or imides. The formation ofcompounds of these types would require decomposition of the amine and inthe research leading to the development of this invention, no evidenceof I such decomposition has been found.

As indicated above, the preferred reaction products are those which areprepared from substituted aliphatic dicarboxylic acid anhydrides inwhich the substituent group is a hydrocarbon radical containing at leastsix carbon atoms. Reaction products of acid anhydrides having as asubstituent an alkenyl group containing at least six carbon atoms areparticularly advantageous. The especially preferred products are thoseobtained with the use of substituted aliphatic dicarboxylic acidanhydrides in which the substituent contains a relatively large numberof carbon atoms, for example, 8 to 12 carbon atoms.

The substituted dicarboxylic acids employed in preparing the newanti-corrosion agents are all derivatives of the homologous series ofwhich malom'c acid is the first member. Higher acids of this seriesinclude succinic, maleic, glutaric, adipic, pimelic, suberic, azelaicand sebacic acids, decane-dicarboxylic acid, undecane-dicarboxylic acid,etc. The substituent may be any hydrocarbon radical and preferablycontains at least 6 carbon atoms; Examples of such substituents includealkyl and alkenyl groups of any chain length; aryl groups, such asphenyl, tolyl, xylyl, butylphenyl, naphthyl, xenyl, etc.; aralkyigroups, such as benzyl, phenylethyl, methylbent yl, etc.; andcycloalkyl, such as cyclohexyl, methylcyclohexyl, ethylcyclohexyl,cycloheptyl, etc. Mixtures of dicarboxylic acids containing diiferentsubstituents may likewise be employed.

Examples of tertiary amines which may be reacted with the substitutedaliphatic dicarboxylic acid anhydrides in preparing the newanti-corrosion agents are the following: trimethylamine, triethylamine,triamylamine, triethanolamine, tribenzylamine,tristearyltriethanolamine, tri ethanolamine-ethylphosphatidic acid, andpy-'- ridine.

, Any of the above, or mixtures thereof, or various oxygen, halogen,sulfur, nitrogen, or phosphorus derivatives of these compounds may bereacted with the above-defined class of dicarboxylic acids to form theanti-corrosion agents employed in mineral oil compositions in accordancewith the invention.

The mineral oil compositions of the present in vention may be of varioustypes having special properties adapting them for certain particularapplications. Thus, they may be lubricating oil compositions. rangingfrom light machine and household oils to heavy lubricants for largeinternal combustion engines, including diesel engines. Alternatively,they may be of the nature of protective oils or greases, such asslushing oils or gun greases, or they may be adapted for use asmetalworking oils or the like. They are particularly well suited for use assteam turbine oils since they provide adequate protection againstrusting and corrosion in the presence of water and water vapor, and donot readily emulsify They may also be fuel oil compositions, includingdiesel engine fuels and domestic burner oils, whereby the anti-corrosionagent protects the tanks in which such oil is stored against corrosionbrought about by the water with which such oils are often contaminated,as for example in the case of marine fuel oils which usually arecontaminated with salt water, giving rise to very serious corrosion inthe storage bunkers.

Regardless of the particular type of composition or the specific use towhich it is adapted, the new compositions of the invention are preparedsimply by mixing the herein-defined anti-corrosion agents with thedesired mineral oil base to form a homogeneous composition. These agentsfunction independently of other common oil additives, e. g.,anti-oxidants, detergents, viscosity index improvers, anti-foam agents,demulsifyiiig agents, pour point depressants, etc., and accord ingly maybe used in conjunction with such addi tives. They may be employed invarying amounts depending upon the severity of the corrosion con--ditions under which the composition will be used.- Ordinarily, however,lubricating compositions contain less than about 1 per cent, usuallybetween about 0.01 and about 0.5 per cent, of the anti-corrosion agent,based on the weight of the base oil, whereas slushing oil types ofcompositions may contain up to 10 or more per cent by weight of thecorrosion inhibitor to provide adequate protection against corrosionduring storage for long periods of time under very drastic climaticconditions.

In testing and demonstrating the efficiency of the new compositions inproviding protection against corrosion, use may be made of the socalledASTM Corrosion Test which is a'modification of that specified in theASTM Standards on Petroleum Products and Lubricants, Septem-- ber, 1945,designated as ASTM D-665-44T. In brief,-this test consists in placing a300 ml. sample of the oil or oil composition to be tested in a 400 ml.beaker which is immersed in a constant temperature bath maintained at140 F. The beaker is fitted with a cover provided with openings for astainless steel motor-driven stirrer and for insertion of a standardsteel test bar, /2' inch in diameter and 5 inches long, which has beenvery carefully cleaned and polished just prior to the test. The stirreris started and when the oil sample in the beaker reaches a steadytemperature of 140 F. the test bar is inserted in the proper opening andhangs suspended from the beaker cover. After 30 minutes of stirring, 30m1. of distilled water are added to the beaker, and stirring is thencontinued for 48 hours, after whi h time the test bar is removed andexamined for rust spots. If there are no rust spots on the steel bar,the sample is said to pass this test. Any rusting of the bar indicatesfailure.

In a modification of the above-described test, artificial sea waterhaving the following composition:

Parts by Weight NaCl 25.0 MgClz-GHzO 11.0 Na2SO4 4.0 CaClz 1.2 Distilledwater 1000.0

corrosion agent and a refined lubricating oil having the followingspecifications:

Approximately 227 parts by weight (1 mol) of a technical grade oftriamylamine were added in small increments to approximately 266 partsby weight; (1 mol) of mixed alkenyl succinic acid anhydrides. The lattermaterial was a lightyellow, zoily liquid, commercial product consistingof a mixture of alkenyl succinic acid anhydrides in which the alkenylsubstituent contained an average of from about to 12 carbon atoms.During the addition of the amine, heat was evolved and the mixture wasmaintained at about 250 F. for about 5 minutes. The resulting reactionproduct was a dark viscous liquid. A composition consisting of 0.10 percent by weight of this product and 99.9 per cent by weight of theabove-described base oil successfully passed both of thehereinbefore-described corrosion tests.

The base oil itself failed to pass either of these tests, as did acomposition consisting Of 0.10 per cent by weight of the alkenylsuccinic acid anhydrid dissolved in the base oil.

Example II Approximately 16 parts by weight of pyridine were reactedwith approximately 54 parts by weight of the mixed alkenyl succinic acidanhydrides employed in Example I, substantially as described in thatexample. The reaction product obtained was a very viscous yellow liquid.A composition consisting of 0.05 per cent by Weight of this productdispersed in the base oil successfully passed both of thehereinbefore-described corrosion tests.

Example III Approximately 130 parts by weight ofdiethanolamine-ethyl-phosphatidic acid were reacted with approximately26 parts by weight of the mixed alkenyl succinic acid anhydridesemployed in Example I, substantially as described in that example. Thereaction product obtained was a brown viscous liquid. A compositionconsisting of 0.10 per cent by weight of this product dispersed in thebase oil successfully passed both of the hereinbefore-describedcorrosion tests.

Example IV the class of substituted aliphatic dicarboxylic acidanhydrides and tertiary amines. For example, by maintaining a mixture oftriethanolamine and the mixed alkenyl succinic acid anhydrides describedin Example I at a temperature of about 250 F. for a few minutes, a clearamber plastic solid is obtained which is an excellent rust preventive.The reaction product between the mixed alkenyl succinic acid anhydridesand triethylamine, prepared as described in the examples, is a veryviscous sticky liquid which when added to the base oil so as to bepresent in the amount of 0.10 per cent by weight produces a compositionthat passes both of the hereinbefore described corrosion tests. Similarproducts are obtained by combining, under the conditions described inthe examples, alpha-cyclohexylmalonic acid anhydride andtriamylamine;alpha-hexyldecyl-malonic acid anhydride andtriethanolamine; alpha-n-octyl-nonane dicarboxylic acid anhydride andpyridine; and alpha-benzyl-succinic acid anhydride and triamylamine.

This application is a continuation-in-part of my co-pending applicationsSerial No. 708,183

' and Serial No. 703,186, filed on November 6, 1946,

now abandoned.

Other modes of applying the principle of my invention may be employedinstead of those explained, change being made as regards the methods ormaterials employed, provided the products defined by any of thefollowing claims be obtained.

I claim:

1. An improved mineral oil composition comprising a major amount of amineral oil and dissolved in said oil a minor amount of a waterinsolublereaction product obtained by a process comprising maintaining a mixtureof about equimolecular quantities of mixed alkenyl-substituted succinicacid anhydrides in which the alkenyl substituents contain an average ofabout 10 to 12 carbon atoms and an amine selected from the groupconsisting of trimethylamine, triethylamine, triamylamine,triethanolamine, tribenzylamine, tristearyl-triethanolamine,triethanolamine-ethylphosphatidic acid and pyridine, at an elevatedreaction temperature of about 250 F. for about 5 minutes, the amount ofsaid reaction product being sufficient to impart corrosion-inhibitingproperties to said composition.

2. The composition of claim 1 in which the amine is triamylamine.

3. The composition of claim 1 in which the amine is pyridine.

4. The composition of claim 1 in which the amine istriethanolamine-ethylphosphatidic acid.

5. The composition of claim 1 in which the amine istristearyl-triethanolamine.

ALBERT G. ROCCHINI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,109,941 DAlelio Mar. 1, 19382,182,178 Pinkernelle Dec. 5, 1939 2,342,114 Blair Feb. 22, 19442,417,833 Lincoln et a1 Mar. 25, 1947 2,481,585 Freeman Sept. 13, 19492,490,744 Trigg Dec. 6, 1949

1. AN IMPROVED MINERAL OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF AMINERAL OIL AND DISSOLVED IN SAID OIL A MINOR AMOUNT OF A WATERINSOLUBLEREACTION PRODUCT OBTAINED BY A PROCESS COMPRISING MAINTAINING A MIXTUREOF ABOUT EQUIMOLECULAR QUANTITIES OF MIXED ALKENYL-SUBSTITUTED SUCCINICACID ANHYDRIDES IN WHICH THE ALKENYL SUBSTITUENTS CONTAIN AN AVERAGE OFABOUT 10 TO 12 CARBON ATOMS AND AN AMINE SELECTED FROM THE GROUPCONSISTING OF TRIMETHYLAMINE, TRIETHYLAMINE, TRIMYLAMINE,TRIETHANOLAMINE, TRIBENZYLAMINE, TRISTEARYL-TRIETHANOLAMINE,TRIETHANOLAMINE-ETHYLPHOSPHATIDIC ACID AND PYRIDINE, AT AN ELEVATEDREAFTION TEMPERATURE OF ABOUT 250* F. FOR ABOUT 5 MINUTES, THE AMOUNT OFSAID REACTION PRODUCT BEING SUFFICIENT TO IMPART CORROSION-INHIBITINGPROPERTIES TO SAID COMPOSITION.